package com.my.yc.d0304;

import javax.servlet.*;
import javax.servlet.annotation.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.net.URLEncoder;

@WebFilter(filterName = "LoginFilter", value={"/hello.html", "/pub/check.html", "/UploadServlet"})
public class LoginFilter implements Filter {
    public void init(FilterConfig config) throws ServletException {
        System.out.println("LoginFilter 初始化");
    }

    public void destroy() {
        System.out.println("LoginFilter 销毁");
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
        // 判断是否登录 =》 在会话中查找 loginedUser 属性
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpSession session = httpServletRequest.getSession();
        if (session.getAttribute("loginedUser") == null){
            // 说明未登录
            HttpServletResponse httpServletResponse = (HttpServletResponse) response;
           // 获取应用上下文对象
            ServletContext servletContext = request.getServletContext();
            // contextPath => /webdemo_war_exploded
            String contextPath = servletContext.getContextPath();
            // 编码
            String url = contextPath + "/" + URLEncoder.encode("验证码", "utf-8") + ".html";
            // 跳转登录页
            httpServletResponse.sendRedirect(url);

            // 保存当前访问的页面地址
            String requestURI = httpServletRequest.getRequestURI();
            System.out.println("requsetURI = " + requestURI);
            // 将该地址保存到会话
            session.setAttribute("requestURI", requestURI);
            // 返回 不允许访问目标资源 不能执行 chain doFilter
            return;
        }
        System.out.println("EncodingFilter 执行过滤(前)");
        chain.doFilter(request, response);
        System.out.println("EncodingFilter 执行过滤(后)");

    }
}
